Robin America eh72 User manual

SERVICE

MANUAL

EH72

ENGINES

Model

PUB-ES1545

Rev. 09/03

940 Lively Blvd. • Wood Dale, IL 60191 • Phone: 630-350-8200 • Fax: 630-350-8212

e-mail: [email protected] • www.robinamerica.com

CONTENTS

Section Title Page

1. SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2. PERFORMANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

3. FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4. GENERAL DESCRIPTION OF ENGINE COMPONENTS . . . . . . . . . . . . . . . . . . . . 5

5. DISASSEMBLY AND REASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

5-1 PREPARATIONS AND SUGGESTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

5-2 SPECIAL TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

5-3 DISASSEMBLY PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

5-4 REASSEMBLY PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

5-5 BREAK-IN OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

6. MAGNETO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

7. LUBRICATION SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

8. CARBURETOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

9. ELECTRIC STARTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

10. TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

10-1 NO ENGINE OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

10-2 STARTING DIFFICULTIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

10-3 INSUFFICIENT OUTPUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

10-4 OVERHEAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

10-5 ROUGH IDLING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

10-6 HIGH ENGINE OIL CONSUMPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

10-7 HIGH FUEL CONSUMPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

10-8 DETONATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

10-9 ENGINE MISFIRE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

11. INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

12. SERVICE DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

12-1 STANDARD DIMENSIONS AND SERVICE LIMITS . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

12-2 TIGHTENING TORQUE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

12-3 OIL GRADE CHART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

13. MAINTENANCE AND STORAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

13-1 DAILY MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

13-2 PERIODIC MAINTENANCE SCHEDULE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

13-3 ENGINE STORAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

– 1 –

1. SPECIFICATIONS

Model EH72D

Type

Air-Cooled, 4-Stroke, V-Twin Cylinder,

Horizontal P.T.O. shaft, OHV Gasoline Engine

Bore stroke mm (in.) 2 - 84 x 65 (3.31 x 2.56)

Displacement cm

3

(cu. in.) 720 (43.9)

Compression Ratio 8.1

Continuous Output kW (HP) / r.p.m. 13.4 (18.0) / 3600

Maximum Output kW (HP) / r.p.m. 18.6 (25.0) / 3600

Maximum Torque N

•

m / r.p.m.

(kgf

•

m / r.p.m.)

(ft

•

lb. / r.p.m.)

53.6 / 2500

(5.5 / 2500)

(39.78 / 2500)

Direction of Rotation Counterclockwise as viewed from P.T.O. shaft side

Cooling System Forced Air Cooling

Valve Arrangements Overhead Valve (OHV)

Lubrication Full pressure type with oil Cooler

Lubricant Automotive Engine Oil SAE #20, #30 or 10W-30; Class SE or higher

Capacity of Lubricant L (U.S. gal.) 1.55 (0.41)

Carburetor Down Draft, Float Type (With Accel Pump)

Fuel Automotive Unleaded Gasoline

Fuel Feed System Diaphragm Pump (Pulse type)

Ignition System Flywheel Magneto (Solid State)

Spark Plug NGK-BPR6ES

Charging Capacity V - A 12 - 15 or 12 - 30

Starting System Electric Starter

Governor System Centrifugal Flyweight Type

Air Cleaner Double Element Type

Dry Weight kg (lb.) 46 (101.3)

Dimension (L W H)

mm (in.)

317 477 475 (12.5 18.8 18.7)

Specifications are subject to change without notice.

– 2 –

2. PERFORMANCE

2-1 MAXIMUM OUTPUT

The maximum output is the output of an engine with its throttle valve fully opened under the condition that all

the moving parts are properly worn in after the initial break-in period.

A new engine may not produce full maximum output while its moving parts are still not broken-in.

NOTE :

Power curves shown in the following charts are made in conformity to SAE internal combustion engine

standard test code J1349

2-2 CONTINUOUS RATED OUTPUT

The continuous rated output is the output of an engine at optimum governed speed which is most favorable

from the view point of engine's life and fuel consumption.

When the engine is installed on a certain equipment, it is recommended that the continuous output required

from the engine be kept below this continuous rated output.

2-3 MAXIMUM TORQUE

The maximum torque is the torque at the output shaft when the engine is producing maximum output at

certain revolution.

– 3 –

2-4 PERFORMANCE CURVES

EH72D

2000 2400 2800 3200 3600

10

(13.4)

5

(

6.7

)

15

(20.1)

20

(

26.8

)

REVOLUTION r.p.m

HORSEPOWER

kW

(

HP

)

TORQUE

N-m

(

kgf-m

)

55

(

5.61

)

45

(

4.59

)

CONTINUOUS

RATED HP

RECOMMENDED

HORSEPOWER RANGE

MAXIMUM TORQUE

MAXIMUM HORSEPOWER

– 4 –

3. FEATURES

Highly rigid structure

High-carbon steel, forged crank shaft

Light-weight , tough alminum forged connectiong rod

Ball-bearing

Special cast iron cylinder liner

Long-lasting structure

Forced pressure lubrication of crankshaft by directly connected trochoid pump

Standard equipped oil cooler ensures a good lubrication environment

Ball bearing installed in the throttle bearing of the carbureter

Reliability

Unusually high dust proofing by a double compartment air cleaner and inner vent type carbureter

Carbureter equipped with acceleration pump, and receives excellent throttle response.

A fine distribution suction pipe and effective combustion chamber shape provide greater cubustion

stability and reduced gas emissions

Compact

Center height 133.3mm and 25HP

90 V2 cylinder built in crankcase

– 5 –

Fig. 4-1

Fig. 4-2

Fig. 4-3

4. GENERAL DESCRIPTION OF ENGINE COMPONENTS

ROBIN EH72D engine is air-cooled, 4-stroke, twin-cylinder, OHV arrangement gasoline engine. The twin-

cylinder is located in the angle of 90 degree; #1 cylinder is in the RH side and #2 cylinder in LH side as

viewed from flywheel (cooling fan) side.

4-1 CYLINDER AND CRANKCASE

The twin-cylinder and crankcase is single piece

aluminum die-casting.

The cylinder liner, made of special cast iron, is

molded into the aluminum casting.

The crankcase has a mounting surface on the output

shaft side, where the main bearing cover is attached.

4-2 MAIN BEARING COVER

The main bearing cover is an aluminum die-casting,

which is mounted on the output shaft side of the

crankcase.

Pilots and bosses are machined on the cover for

direct mounting of the engine onto such machines as

generators and pumps.

It is easy to inspect inside of the engine, after

removing the main bearing cover.

4-3 CRANKSHAFT

The crankshaft is forged carbon steel, and the crank

pin is induction-hardened.

The output end of the shaft has a crankshaft gear

pressed into position.

Engine oil passages are provided onto the journal

and pin portions of crankshaft for lubrication.

4-4 CONNECTING ROD AND PISTON

The connecting rod is forged aluminum alloy, and its

large and small ends function as bearings.

The piston is an aluminum alloy casting, and carries

two compression rings and one oil ring.

– 6 –

Fig. 4-4

4-5 PISTON RINGS

The piston rings are made of special cast iron.

The profile of the top ring is barrel face and the second ring has a tapered face.

The oil ring is designed for better sealing and less oil consumption, in combination with 3 pieces.

4-6 CAMSHAFT

The camshaft is made of special cast iron and

camshaft gears are casted together in one piece.

Each 2 cam robs are provided for intake and

exhaust valves correspondingly.

Both sides of the shaft fit into the plane bearings on

the crankcase and main bearing cover.

TOP

RING

SECOND

RING

OIL

RING

1

2

3

BARREL

TAPER

COMBINATION

RING

1

2

3

Fig. 4-5

Fig. 4-6

– 7 –

4-7 CYLINDER HEAD

The cylinder head is an aluminum die-casting which

utilizes semi-spherical type combustion chamber for

the high combustion efficiency.

Fig. 4-7

4-8 VALVE ARRANGEMENT

The intake valve is located on flywheel side of the

cylinder head.

The cooling fins and passages design lead cooling

air to the exhaust valve area for the optimum

cooling.

Hard alloy valve seats are molded in the cylinder

head.

INTAKE VALVEEXHAUST VALVE

Fig. 4-8

4-9 GOVERNOR SYSTEM

The governor is a centrifugal flyweight type which

ensures constant operation at the selected speed

against load variations.

The governor gear with governor weights is installed

inside of main bearing cover and driven by the

crankshaft.

GOVERNOR

GEAR

Fig. 4-9

– 8 –

4-10 COOLING SYSTEM

The large fins on the flywheel provide sufficient

cooling air capacity for cylinder and cylinder head.

The cylinder baffle helps the cooling air flow

efficiently.

4-11 LUBRICATION SYSTEM

The engine is furnished with full pressure lubrication

system.

The trochoid type oil pump is driven by crankshaft

and delivers pressurized engine oil through the full-

flow type oil filter to the journal and pin portions of

crankshaft and camshaft.

4-12 IGNITION SYSTEM

The ignition system is a transistor controlled

magneto ignition system which consists of a flywheel

and an ignition coil with a built-in transistor installed

onto the crankcase.

FLYWHEEL

IGNITION COIL

Fig. 4-10

CHARGE COIL

CABLE, EXTENDED

REGULATOR

Fig. 4-11b

CHARGE COIL

REGULATOR

Fig. 4-11a

4-13 CHARGING SYSTEM

Multipolar charging coil is provided inside of flywheel. Charging capacity is 12V-15A or 12V-30A.

(12V-15A) (12V-30A)

– 9 –

4-14 CARBURETOR

The engine is equipped with a down draft carburetor

that has a float controlled fuel system and a fixed

main jet.

The carburetors are calibrated carefully for the sure

starting, low fuel consumption and sufficient output.

Fuel cut solenoid valve is provided to prevent engine

running on when the key switch is turned to off.

Accelerator-pump is provided for obtaining quick and

good throttle response.

4-15 AIR CLEANER

The air-cleaner is a heavy-duty type with a dual

element system ; primary side is urethane foam

(half-wet) and secondary side is dry type.

ACCELERATOR-PUMP

FUEL CUT

SOLENOID VALVE

Fig. 4-12

URETHANE FOAM

ELEMENT

WING NUT

CLEANER COVER

Fig. 4-13

4-16 FUEL PUMP

The engine is equipped with a diaphragm type fuel

pump which is operated by the crankcase inside

vacuum pressure.

FUEL PUMP

Fig. 4-14

– 10 –

4-17 SECTIONAL VIEW OF ENGINE

CARBURETOR

OIL PUMP

IGNITION COIL

FLYWHEEL

INTAKE MANIFOLD

OIL PUMP FILTER

MAIN BEARING COVER

P.T.O.SHAFT

Fig. 4-15

– 11 –

Fig. 4-16

– 12 –

5. DISASSEMBLY AND REASSEMBLY

5-1 PREPARATIONS AND SUGGESTIONS

When disassembling the engine, memorize the locations of individual parts so that they can be reassembled

correctly. If you are uncertain of identifying some parts, it is suggested that tags be attached to them.

Have boxes ready to keep disassembled parts by group.

To prevent losing and misplacing, temporarily assemble each group of disassembled parts.

Carefully handle disassembled parts, and clean them with washing oil if necessary.

Use the correct tools in the correct way.

When disconnecting electric wirings, be sure to hold and disconnect the connector housing.

5-2 SPECIAL TOOLS

No Special Tool is needed for disassembling and reassembling the engine.

For pulling off the flywheel, universal type puller being popular in the market place as shown in the illustration

is needed.

FLYWHEEL PULLER

Fig. 5-1

Tool No. Tool Use

228-95001-17

Flywheel puller with bolt

EH63,64,65,72 / DY30,35,41,42

– 13 –

5-3 DISASSEMBLY PROCEDURES

Step Parts to remove Remarks and procedures Fasteners

1 Engine oil drain

Drain engine oil by removing plugs located on

both side of crankcase.

2 Muffler cover

M6 x 12 : 6 pcs.

3 Muffler M8 nut : 4pcs.

4 Muffler bracket

M8 x 16 bolt and

washer : 2pcs.

STEP 4

STEP 3

STEP 2

A

MUFFLER

BLACKET

MUFFLER

COVER

M6 FLANGE

BOLT : 2 pcs.

M6 FLANGE

BOLT : 2 pcs.

M8 BOLT &

WASHER : 2 pcs.

M6 FLANGE

BOLT : 2 pcs.

GASKET

MUFFLER

M8 SUS FLANGE

NUT : 4 pcs.

STEP 1

GASKET

OIL DRAIN PLUG

(

ON BOTH SIDE

)

OIL FILLER CAP

GUIDE, oil level

OIL LEVEL GAUGE

A

Fig. 5-2

WING NUT

STEP 5

CLEANER

COVER

CLEANER

ELEMENT

STEP 6

CLEANER BASE

HOSE CLAMP

M6 FLANGE

BOLT :

3 pcs.

BREATHER PIPE

HOSE CLAMP

– 14 –

Step Parts to remove Remarks and procedures Fasteners

5 Air cleaner cover and elements Remove breather pipe from #1 cylinder head.

6 Air cleaner base

M6 x 12 : 3 pcs.

BREATHER PIPE

Fig. 5-4

Fig. 5-3

– 15 –

Step Parts to remove Remarks and procedures Fasteners

7 Blower housing

M6 x 12 : 2 pcs.

M6 x 14 : 6 pcs.

8 Chock control lever and link

(1) Remove the choke knob.

(2) Remove the choke contol link.

M6 bolt : 1 pc.

CHOKE

CONTROL ROD

RETURN

SPRING

WAVED

WASHER

LINK PIVOT

CHOKE

CONTROL

LINK

CHOKE

KNOB

CLAMP

M5 TAPPING

SCREW : 1 pc.

BLOWER HOUSING

M6 FLANGE

BOLT : 6 pcs

M6 FLANGE

BOLT : 2 pcs

STEP 7

STEP 8

Fig. 5-5

STEP 9

M8 FLANGE

BOLT : 2 pcs.

CARBURETOR

GASKET,

carburetor

– 16 –

Step Parts to remove Remarks and procedures Fasteners

9

Carburetor

At first remove fuel pipe.

Take out carburetor along with governor rod

and rod spring.

M8 x 80 : 2 pcs.

FUEL PIPE

Fig. 5-7

Fig. 5-6

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